1. Field of the Invention
The present invention relates to a disorder detecting device for detecting a disorder involving equipment connected to a network, by only resorting to a first physical layer out of the seven layers implemented as the standards of network protocol for open system interconnection (OST) which was introduced by ISO in order to ensure open type interconnection.
2. Description of the Related Art
In a conventional local area network (LAN), remote subnetworks are connected through a wide area network (WAN). However, because in recent years data are communicated through LANs at a high speed in wide areas, lines for data communication based on a WAN protocol come to be substituted for fiber optical cables based on a LAN protocol such as 100 Base-FX (LAN Standards IEEE802.3U) to enable direct communication between remote LANs.
FIG. 8 is a block diagram to illustrate the outline of such a conventional LAN network system.
This LAN network system 100 comprises a high level LAN-A110 containing a management equipment 111 to manage the network, and a high level equipment 112, and low level LAN-B120A and LAN-C120B each containing a plurality of user units 121. The LAN-A10, and LAN-B120A and LAN-C120B are communicably interconnected through routers 130 to serve as a connector. The direction of data traffic from the high level LAN-A10 to the low level LAN-B120A and LAN-C120B is taken as downward while the direction of data traffic from the low level LAN-B120A and LAN-C120B to the high level LAN-A110 as upward.
The router 130 is capable of photo/electric conversion of signals, and comprises high level routers 130A which communicably connect with LAN-A110 via electric cables 140A composed of a twist pair cable through which data are communicated on 10/100Base-TX, and low level routers 130B which communicably connect with LAN-B120A and LAN-C120B via electric cables 140B through which data are communicated on 10/100Base-TX.
The high level routers 130A and the low level routers 130B are communicably interconnected via fiber optical cables 150 through which data are communicated on 100Base-FX.
In the LAN network system 100 as configured above, the management equipment 111 in the higher level of network can switch off power to the components (high level router 130A, low level router 130B and user units 121) including user units 121 oppositely positioned in the lower level of network, or detect cable disorders possibly arising along communication routes in the downward direction containing the management equipment itself, by resorting to an echo command (so-called ping) as defined in the internet control message protocol (ICMP) applicable to the third layer out of the seven layers for OSI.
However, according to the conventional LAN network system 100, although it is possible for a personal computer (PC) with a communication function or a router 130 both provided with protocols applicable up to the third layer, to detect disorders in message cables by resorting to the echo command, it is impossible for a bridge, switch or repeater which serves as a mediator for the communication of data based on the second layer protocol and are provided only with protocols up to the second layer to detect disorders in message cables, despite that they are permitted to check electric or optical links through which data are communicated on the first layer protocol. This poses a problem.
In view of these problems, this invention has been proposed, and its object is to provide a device which will allow even equipment devoid of OSI protocols applicable to the third or higher layers to detect a disorder in a message cable by only resorting to a physical layer or the first layer.
To attain the above object, the disorder detecting device of this invention arranged between high level equipment and low level equipment of a network, to transmit communication data between the high level equipment and the low level equipment, in order to serve as open systems interconnection (OSI), and to implement OSI protocols for the first layer or up to the second layer, comprises a monitoring means to monitor a upside-originated idle signal from the high level equipment or a downside-originated idle signal from the low level equipment using the protocol for the first layer; and a disorder detecting means to detect not only a disorder involving a component of the network but a disorder involving the disorder detecting device itself, based on the result obtained by the monitoring means as a result of monitoring the upside-originated signal or the downside-originated signal.
Thus, according to this invention, even if a LAN contains only protocols for the first layer or at maximum for the second layer for OSI, it can detect, provided that it incorporates a disorder detecting device of this invention, not only a disorder involving a component of its network but a disorder of the device itself, based on the monitoring result of an upside-originated idle signal or a downside-originated idle signal. Therefore, the LAN with the disorder detecting device of this invention can detect a disorder involving a component of its network (disorder involving a communication route), by using only its physical layer or the first layer.
The disorder detecting device of this invention comprises a fixed pattern memory means to store fixed patterns correspondent with disorders possibly involving the components of the network; and a disorder notifying means which reads out a fixed pattern correspondent with a disorder as detected by the disorder detecting means from the fixed pattern memory means, and transmits the fixed pattern to the high level equipment or to the low level equipment using the protocol for the first layer.
Thus, according to the disorder detecting device of this invention, fixed patterns are stored in advance in correspondence with disorders likely to happen; an appropriate fixed pattern is read out in correspondence with a disorder as detected by the disorder detecting means; and the fixed pattern is transmitted to high or low level equipment based on the first layer protocol. Thus, even if a LAN contains only protocols for the first layer or at maximum for the second layer for OSI, it can inform, provided that it incorporates a disorder detecting device of this invention, high or low level equipment of a disorder involving a component of the network (disorder involving a message route).
According to the disorder detecting device of this invention, the disorder notifying means transmits the fixed pattern using a communication line used for transmitting communication data between the high level equipment and the low level equipment.
Thus, even if a LAN contains only protocols for the first layer or at maximum for the second layer for OSI, it can inform, provided that it incorporates a disorder detecting device of this invention, high or low level equipment of a disorder involving a component of the network (disorder involving a message route), by only using a communication line used for the transmission of communication data between the high level equipment and the low level equipment, that is, by only using a physical layer or the first layer.
According to the disorder detecting device of this invention, the disorder notifying means transmits the fixed pattern, using a dedicated line different from the communication line used for transmitting communication data between the high level equipment and the low level equipment.
Thus, even if a LAN contains only protocols for the first layer or at maximum for the second layer for OSI, it can inform, provided that it incorporates a disorder detecting device of this invention, high or low level equipment of a disorder involving a component of the network (disorder involving a message route), by only using a dedicated line different from the communication line used for the transmission of communication data between the high level equipment and the low level equipment, that is, by only using a physical layer or the first layer.
According to the disorder detecting device of this invention, the disorder notifying means transmits the fixed pattern using light having the same wavelength with that of light passed through a communication cable for transmitting communication data between the high level equipment and the low level equipment.
Thus, even if a LAN contains only protocols for the first layer or at maximum for the second layer for OSI, it can inform, provided that it incorporates a disorder detecting device of this invention, high or low level equipment of a disorder involving a component of the network (disorder involving a message route), by only using light having the same wavelength with that of light used for the transmission of communication data between the high level equipment and the low level equipment, that is, by only using a physical layer or the first layer.
According to the disorder detecting device of this invention, the disorder notifying means transmits the fixed pattern using light having a wavelength different from that of light passed through a communication cable for transmitting communication data between the high level equipment and the low level equipment.
Thus, even if a LAN contains only protocols for the first layer or at maximum for the second layer for OSI, it can inform, provided that it incorporates a disorder detecting device of this invention, high or low level equipment of a disorder involving a component of the network (disorder involving a message route), by only using light having a wavelength different from that of light used for the transmission of communication data between the high level equipment and the low level equipment, that is, by only using a physical layer or the first layer.
According to the disorder detecting device of this invention, notification of a fixed pattern by the disorder notifying means to the high level equipment occurs in response to a notification request from the high level equipment.
Thus, because according to the disorder detecting device of this invention, a fixed pattern is transmitted to high level equipment in response to a notification request from the high level equipment, it is possible for the high level equipment to identify the nature of a disorder involving a component of the network (disorder involving a message route), based on the fixed pattern thus transmitted.
According to the disorder detecting device of this invention, notification of a fixed pattern by the disorder notifying means to the high level equipment occurs at specified time intervals.
Thus, according to the disorder detecting device of this invention, high level equipment can check at specified time intervals the happening of a disorder that may involve a component of the network (disorder involving a message route), and to identify the nature of the disorder.